ColorBlock.cpp

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/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
 
/*
 * This file is based on a similar file from the NVIDIA texture tools
 * (http://nvidia-texture-tools.googlecode.com/)
 *
 * Original license from NVIDIA follows.
 */
 
/* This code is in the public domain - <castanyo@yahoo.es> */
 
#include <ColorBlock.h>
#include <Common.h>
#include <Image.h>
 
#if 0
/* Get approximate luminance. */
inline static uint colorLuminance(Color32 c)
{
  return c.r + c.g + c.b;
}
 
/* Get the euclidean distance between the given colors. */
inline static uint colorDistance(Color32 c0, Color32 c1)
{
  return (c0.r - c1.r) * (c0.r - c1.r) + (c0.g - c1.g) * (c0.g - c1.g) +
         (c0.b - c1.b) * (c0.b - c1.b);
}
#endif
 
ColorBlock::ColorBlock(const uint *linearImage)
{
  for (uint i = 0; i < 16; i++) {
    color(i) = Color32(linearImage[i]);
  }
}
 
ColorBlock::ColorBlock(const ColorBlock &block)
{
  for (uint i = 0; i < 16; i++) {
    color(i) = block.color(i);
  }
}
 
ColorBlock::ColorBlock(const Image *img, uint x, uint y)
{
  init(img, x, y);
}
 
void ColorBlock::init(const Image *img, uint x, uint y)
{
  init(img->width(), img->height(), (const uint *)img->pixels(), x, y);
}
 
void ColorBlock::init(uint w, uint h, const uint *data, uint x, uint y)
{
  const uint bw = MIN(w - x, 4U);
  const uint bh = MIN(h - y, 4U);
 
  /* Blocks that are smaller than 4x4 are handled by repeating the pixels.
   * @@ That's only correct when block size is 1, 2 or 4, but not with 3. :(
   * @@ Ideally we should zero the weights of the pixels out of range. */
 
  for (uint i = 0; i < 4; i++) {
    const int by = i % bh;
 
    for (uint e = 0; e < 4; e++) {
      const int bx = e % bw;
      const uint idx = (y + by) * w + x + bx;
 
      color(e, i).u = data[idx];
    }
  }
}
 
void ColorBlock::init(uint w, uint h, const float *data, uint x, uint y)
{
  const uint bw = MIN(w - x, 4U);
  const uint bh = MIN(h - y, 4U);
 
  /* Blocks that are smaller than 4x4 are handled by repeating the pixels.
   * @@ That's only correct when block size is 1, 2 or 4, but not with 3. :(
   * @@ Ideally we should zero the weights of the pixels out of range. */
 
  uint srcPlane = w * h;
 
  for (uint i = 0; i < 4; i++) {
    const uint by = i % bh;
 
    for (uint e = 0; e < 4; e++) {
      const uint bx = e % bw;
      const uint idx = ((y + by) * w + x + bx);
 
      Color32 &c = color(e, i);
      c.r = uint8(255 * CLAMP(data[idx + 0 * srcPlane],
                              0.0f,
                              1.0f)); /* @@ Is this the right way to quantize floats to bytes? */
      c.g = uint8(255 * CLAMP(data[idx + 1 * srcPlane], 0.0f, 1.0f));
      c.b = uint8(255 * CLAMP(data[idx + 2 * srcPlane], 0.0f, 1.0f));
      c.a = uint8(255 * CLAMP(data[idx + 3 * srcPlane], 0.0f, 1.0f));
    }
  }
}
 
static inline uint8 component(Color32 c, uint i)
{
  if (i == 0) {
    return c.r;
  }
  if (i == 1) {
    return c.g;
  }
  if (i == 2) {
    return c.b;
  }
  if (i == 3) {
    return c.a;
  }
  if (i == 4) {
    return 0xFF;
  }
  return 0;
}
 
void ColorBlock::swizzle(uint x, uint y, uint z, uint w)
{
  for (Color32 &color : m_color) {
    const Color32 c = color;
    color.r = component(c, x);
    color.g = component(c, y);
    color.b = component(c, z);
    color.a = component(c, w);
  }
}
 
bool ColorBlock::isSingleColor(Color32 mask /*= Color32(0xFF, 0xFF, 0xFF, 0x00)*/) const
{
  uint u = m_color[0].u & mask.u;
 
  for (int i = 1; i < 16; i++) {
    if (u != (m_color[i].u & mask.u)) {
      return false;
    }
  }
 
  return true;
}
 
#if 0
bool ColorBlock::isSingleColorNoAlpha() const
{
  Color32 c;
  int i;
  for (i = 0; i < 16; i++) {
    if (m_color[i].a != 0) {
      c = m_color[i];
    }
  }
 
  Color32 mask(0xFF, 0xFF, 0xFF, 0x00);
  uint u = c.u & mask.u;
 
  for (; i < 16; i++) {
    if (u != (m_color[i].u & mask.u)) {
      return false;
    }
  }
 
  return true;
}
#endif
 
#if 0
uint ColorBlock::countUniqueColors() const
{
  uint count = 0;
 
  /* @@ This does not have to be o(n^2) */
  for (int i = 0; i < 16; i++) {
    bool unique = true;
    for (int j = 0; j < i; j++) {
      if (m_color[i] != m_color[j]) {
        unique = false;
      }
    }
 
    if (unique) {
      count++;
    }
  }
 
  return count;
}
#endif
 
#if 0
Color32 ColorBlock::averageColor() const
{
  uint r, g, b, a;
  r = g = b = a = 0;
 
  for (uint i = 0; i < 16; i++) {
    r += m_color[i].r;
    g += m_color[i].g;
    b += m_color[i].b;
    a += m_color[i].a;
  }
 
  return Color32(uint8(r / 16), uint8(g / 16), uint8(b / 16), uint8(a / 16));
}
#endif
 
bool ColorBlock::hasAlpha() const
{
  for (const auto &i : m_color) {
    if (i.a != 255) {
      return true;
    }
  }
  return false;
}
 
#if 0
 
void ColorBlock::diameterRange(Color32 *start, Color32 *end) const
{
  Color32 c0, c1;
  uint best_dist = 0;
 
  for (int i = 0; i < 16; i++) {
    for (int j = i + 1; j < 16; j++) {
      uint dist = colorDistance(m_color[i], m_color[j]);
      if (dist > best_dist) {
        best_dist = dist;
        c0 = m_color[i];
        c1 = m_color[j];
      }
    }
  }
 
  *start = c0;
  *end = c1;
}
 
void ColorBlock::luminanceRange(Color32 *start, Color32 *end) const
{
  Color32 minColor, maxColor;
  uint minLuminance, maxLuminance;
 
  maxLuminance = minLuminance = colorLuminance(m_color[0]);
 
  for (uint i = 1; i < 16; i++) {
    uint luminance = colorLuminance(m_color[i]);
 
    if (luminance > maxLuminance) {
      maxLuminance = luminance;
      maxColor = m_color[i];
    }
    else if (luminance < minLuminance) {
      minLuminance = luminance;
      minColor = m_color[i];
    }
  }
 
  *start = minColor;
  *end = maxColor;
}
 
void ColorBlock::boundsRange(Color32 *start, Color32 *end) const
{
  Color32 minColor(255, 255, 255);
  Color32 maxColor(0, 0, 0);
 
  for (uint i = 0; i < 16; i++) {
    if (m_color[i].r < minColor.r) {
      minColor.r = m_color[i].r;
    }
    if (m_color[i].g < minColor.g) {
      minColor.g = m_color[i].g;
    }
    if (m_color[i].b < minColor.b) {
      minColor.b = m_color[i].b;
    }
    if (m_color[i].r > maxColor.r) {
      maxColor.r = m_color[i].r;
    }
    if (m_color[i].g > maxColor.g) {
      maxColor.g = m_color[i].g;
    }
    if (m_color[i].b > maxColor.b) {
      maxColor.b = m_color[i].b;
    }
  }
 
  /* Offset range by 1/16 of the extents */
  Color32 inset;
  inset.r = (maxColor.r - minColor.r) >> 4;
  inset.g = (maxColor.g - minColor.g) >> 4;
  inset.b = (maxColor.b - minColor.b) >> 4;
 
  minColor.r = (minColor.r + inset.r <= 255) ? minColor.r + inset.r : 255;
  minColor.g = (minColor.g + inset.g <= 255) ? minColor.g + inset.g : 255;
  minColor.b = (minColor.b + inset.b <= 255) ? minColor.b + inset.b : 255;
 
  maxColor.r = (maxColor.r >= inset.r) ? maxColor.r - inset.r : 0;
  maxColor.g = (maxColor.g >= inset.g) ? maxColor.g - inset.g : 0;
  maxColor.b = (maxColor.b >= inset.b) ? maxColor.b - inset.b : 0;
 
  *start = minColor;
  *end = maxColor;
}
 
void ColorBlock::boundsRangeAlpha(Color32 *start, Color32 *end) const
{
  Color32 minColor(255, 255, 255, 255);
  Color32 maxColor(0, 0, 0, 0);
 
  for (uint i = 0; i < 16; i++) {
    if (m_color[i].r < minColor.r) {
      minColor.r = m_color[i].r;
    }
    if (m_color[i].g < minColor.g) {
      minColor.g = m_color[i].g;
    }
    if (m_color[i].b < minColor.b) {
      minColor.b = m_color[i].b;
    }
    if (m_color[i].a < minColor.a) {
      minColor.a = m_color[i].a;
    }
    if (m_color[i].r > maxColor.r) {
      maxColor.r = m_color[i].r;
    }
    if (m_color[i].g > maxColor.g) {
      maxColor.g = m_color[i].g;
    }
    if (m_color[i].b > maxColor.b) {
      maxColor.b = m_color[i].b;
    }
    if (m_color[i].a > maxColor.a) {
      maxColor.a = m_color[i].a;
    }
  }
 
  /* Offset range by 1/16 of the extents */
  Color32 inset;
  inset.r = (maxColor.r - minColor.r) >> 4;
  inset.g = (maxColor.g - minColor.g) >> 4;
  inset.b = (maxColor.b - minColor.b) >> 4;
  inset.a = (maxColor.a - minColor.a) >> 4;
 
  minColor.r = (minColor.r + inset.r <= 255) ? minColor.r + inset.r : 255;
  minColor.g = (minColor.g + inset.g <= 255) ? minColor.g + inset.g : 255;
  minColor.b = (minColor.b + inset.b <= 255) ? minColor.b + inset.b : 255;
  minColor.a = (minColor.a + inset.a <= 255) ? minColor.a + inset.a : 255;
 
  maxColor.r = (maxColor.r >= inset.r) ? maxColor.r - inset.r : 0;
  maxColor.g = (maxColor.g >= inset.g) ? maxColor.g - inset.g : 0;
  maxColor.b = (maxColor.b >= inset.b) ? maxColor.b - inset.b : 0;
  maxColor.a = (maxColor.a >= inset.a) ? maxColor.a - inset.a : 0;
 
  *start = minColor;
  *end = maxColor;
}
#endif
 
#if 0
void ColorBlock::sortColorsByAbsoluteValue()
{
  /* Dummy selection sort. */
  for (uint a = 0; a < 16; a++) {
    uint max = a;
    Color16 cmax(m_color[a]);
 
    for (uint b = a + 1; b < 16; b++) {
      Color16 cb(m_color[b]);
 
      if (cb.u > cmax.u) {
        max = b;
        cmax = cb;
      }
    }
    swap(m_color[a], m_color[max]);
  }
}
#endif
 
#if 0
void ColorBlock::computeRange(Vector3::Arg axis, Color32 *start, Color32 *end) const
{
 
  int mini, maxi;
  mini = maxi = 0;
 
  float min, max;
  min = max = dot(Vector3(m_color[0].r, m_color[0].g, m_color[0].b), axis);
 
  for (uint i = 1; i < 16; i++) {
    const Vector3 vec(m_color[i].r, m_color[i].g, m_color[i].b);
 
    float val = dot(vec, axis);
    if (val < min) {
      mini = i;
      min = val;
    }
    else if (val > max) {
      maxi = i;
      max = val;
    }
  }
 
  *start = m_color[mini];
  *end = m_color[maxi];
}
#endif
 
#if 0
void ColorBlock::sortColors(const Vector3 &axis)
{
  float luma_array[16];
 
  for (uint i = 0; i < 16; i++) {
    const Vector3 vec(m_color[i].r, m_color[i].g, m_color[i].b);
    luma_array[i] = dot(vec, axis);
  }
 
  /* Dummy selection sort. */
  for (uint a = 0; a < 16; a++) {
    uint min = a;
    for (uint b = a + 1; b < 16; b++) {
      if (luma_array[b] < luma_array[min]) {
        min = b;
      }
    }
    swap(luma_array[a], luma_array[min]);
    swap(m_color[a], m_color[min]);
  }
}
#endif
 
#if 0
float ColorBlock::volume() const
{
  Box bounds;
  bounds.clearBounds();
 
  for (int i = 0; i < 16; i++) {
    const Vector3 point(m_color[i].r, m_color[i].g, m_color[i].b);
    bounds.addPointToBounds(point);
  }
 
  return bounds.volume();
}
#endif